Vehicle roof systems also known as sunroof systems are widely used in passenger vehicles for selectively opening and closing an opening formed in the roof of the vehicle. A typical vehicle roof system comprises a moveable roof panel and a drive unit for actuating the moveable roof panel between a position to close the opening and a position to expose the opening. A pair of guide rails are fixedly secured to the fixed roof panel, and extend along either lateral side of the roof opening, and the moveable roof panel is supported by these guide rails via sliders so as to be slidable in the fore and aft direction. An electric motor is provided centrally on the front edge of the roof opening, and a pair of push-pull cables connected to the corresponding sliders are actuated by the electric motor as required.
The electric motor may be placed either on the front edge or rear edge of the roof opening. If the electric motor is placed on the rear edge of the roof opening, as this part lacks any stiff member, a rear frame is required to be added to the roof structure for supporting the electric motor. It is possible to do away with the rear frame by using highly stiff guide pipes for guiding the push-pull cables, but this also adds to the weight of the vehicle body, and causes some difficulty in the handling of the assembly including the electric motor and guide pipes. Based on such considerations, it is preferable to place the electric motor on the front edge of the roof opening.
It is proposed in copending application US20100181805A1 (patent document 1) to mount an electric motor on the front edge of the roof opening, and use guide pipes (drive pipes and idle pipes) made of plastic material which are firmly retained by a front frame via pipe retaining members.
Sometimes, in addition to the electric motor, onboard devices such as room lamps and electric switches are attached to the part of the roof surrounding the roof opening, and such devices are required to be placed so as not to interfere with the electric motor. In particular, a room lamp is provided adjacent to a central part of the front edge of the roof opening. To avoid the interference between the electric motor and room lamp, it was proposed in JP2001-130349A (patent document 2) to provide a sub frame below the electric motor for supporting a map lamp, a room lamp and vanity lamps, and combine the electric motor and sub frame as an assembly that can be installed in the vehicle roof as a single unit.
However, according to the vehicle roof structure disclosed in patent document 2, the room lamp and electric motor are placed one above the other in an overlapping relationship in plan view so that the thickness of the vehicle roof (as measured from the lower surface of the roof lining and the upper surface of the roof panel) inevitably increases. To avoid this problem, it is conceivable to place the room lamp at a relatively forward position, and place the electric motor between the room lamp and the front edge of the roof opening. However, this necessitates the front edge of the roof opening to be placed more rearward than desired. If the roof opening is located too far back in the roof, the viewing angle of the vehicle occupant through the roof opening is so upright that the vehicle occupant's field of view is restricted, and the benefits of the sunroof system are diminished.